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Solutions for Steam Service Valve Error?

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erics_guerron123
erics_guerron123 Member Posts: 25
in Strictly Steam

Hello all,

Being new to owning a steam heating system with radiators, I made the mistake of closing the service valve halfway thinking I can control the heat. Now I hear water hammering on these radiators that I did this on. Since hearing the water hammering, I completely opened the service valve and I pitched the radiators to try to get the condensate to flow back to the service valve. But no improvement.

Im thinking of removing the radiators and tipping them over to get the water out or removing the radiator and then using a wet vacuum to suck out all the water. and then connecting them again. Any other solutions? Draining the boiler completely?

Also is it possible for the service valve to be incorrectly pitched? Does it need to be completely vertical or slightly pitched away from the radiator or pitched towards the radiator? Or does this not matter? Thank you!

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 27,150

    Are you sure that valve reopened? Not unheard of for the disc to fall off the bottom of the stem…

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • erics_guerron123
    erics_guerron123 Member Posts: 25
    https://forum.heatinghelp.com/discussion/comment/1887848#Comment_1887848

    can you elaborate? disc?

  • erics_guerron123
    erics_guerron123 Member Posts: 25
    Screenshot 2026-02-13 at 1.44.20 PM.png

    here is an image i found online, where the service valve is slightly pitched away from the radiator (not perfectly vertical), would pitching the service valve away from the radiator help with this issue? how do I do pitch the service valve away from radiator?

  • Big Ed_4
    Big Ed_4 Member Posts: 3,471
    edited February 13

    Never use the service valve to control the heat , you control through the venting .. Plug the vent if you don't want heat ..

    Just open up the service valve to drain the radiator .. They don't hold back steam all that good .

    There was an error rendering this rich post.

  • tylerjgardner
    tylerjgardner Member Posts: 8

    Its sounds like it may not have opened all the way, or its stuck halfway closed. I'm assuming it's one pipe steam? You may have to replace the valve.

  • Captain Who
    Captain Who Member Posts: 682
    edited February 13

    Old supply valves could be on the verge of falling apart and then when you combine that with water hammer, that could seal the deal. There's a metal disc attached with a screw, with a rubber gasket attached that makes the seal when the valve is closed.

    chrome_2026-02-13_14-33-23.jpg
  • erics_guerron123
    erics_guerron123 Member Posts: 25
    https://forum.heatinghelp.com/discussion/comment/1887877#Comment_1887877

    so what’s my solution? I can’t open the service valve anymore than what it already is. Should I Remove the radiator from the service valve and drain it by tipping it over? Or using a wet vacuum?

  • Captain Who
    Captain Who Member Posts: 682
    https://forum.heatinghelp.com/discussion/comment/1887890#Comment_1887890

    To check the valve for damage you have to either remove the bonnet at the top of the valve, which has a hex on it (might not be easy!), or disconnect the radiator and either slide the radiator back on the floor a ways or turn the valve a bit on the pipe. Then look at it to see if the disc has come unattached. There may be water so have lots of towels in case the valve wasn't allowing the water to drain out of the radiator.

    Big Ed_4

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